How to Select the Right Injection Mold

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Ultimate Guide for Selecting the Right Injection Mold

You are about to finalize your part design and are ready to turn your attention toward your mold selection so you can start getting molded components.  Suddenly, what you thought would be a straightforward &#;just-make-a-mold&#; task turns into a universe of decisions with tradeoffs. 

Even more confusing, you have proposals from multiple companies with wildly varying costs. How do you know you&#;re making the right choice for your project and your money?

This guide will help you understand:

• Top 5 considerations in mold selection
• Industry standards for mold classifications
• Questions to prepare to answer
• Red flags to watch out for during the selection process

Five Key Items to Consider Before Selecting a Mold

When you engage a manufacturing partner for your project, they should begin by understanding your part and overall program needs. During this time, Natech engineers focus on five items to help their clients choose the right solution for their project.

Speed to Build

Building a brand new mold is often one of the longest lead times in your project. Molds can be built in just a couple of weeks or mold building can take several months.

When it comes to the speed of mold build, evaluate your true project needs rather than just how quickly it can be built. If you are still trying to prove your concept, you can likely expect a prototype or R&D mold to take 3-6 weeks. If you are ready to run high-volume, a production-ready mold may take upwards of 12-18 weeks.

What is most important is collaborating with your manufacturing partner. Often, there is an intermediary solution or future planning that can help alleviate anxiety with longer lead times. This can include beginning with an R&D mold and building a production mold while you get your first parts in hand, or relying on interchangeable steel inserts with different geometry iterations.

Cost of the Initial Mold Build

With molds ranging from $5,000 to $100,000 or more, it is critical to build this line item into your budget early. An R&D mold for a simple part is going to be much cheaper than a multi-cavity, production-level mold.

If you believe you&#;ll need multiple design iterations, running through several R&D molds might be your best bet, but relying on a $5,000 mold for longevity is going to leave you with quality issues and a headache in the long run.

Several factors impact the cost of your mold, including mold classification (more on that later), the complexity of your part(s), mold cavitation, and specialty molding features.

A responsible injection molding partner will help you understand what goes into your mold building price, and help you get the most bang for your buck.

Project Development Stage

Where you are in your project development stage is a critical factor in mold selection. Typically, it is broken into: Design, Prototype, Pre-Production, Production, and High-Volume.

In the early stages, you can typically expect a lower cost, lower construction quality mold. That is because these stages often include multiple design changes and revisions. Some companies are eager to jump into a production-ready mold as a way to avoid paying for several prototype molds. This can be dangerous, as the cost and time for mold changes and modifications increase substantially for these molds.

On the flip side, some companies producing parts at higher volumes feel nervous about committing to a production mold. These companies end up spending more money in new molds and mold repairs over time, as the prototype molds degrade in quality.

Being realistic about where you are (and where you want to go) in your product development will save you time and money.

Part Geometry or Complexity

Certain part geometry and features require different moldmaking approaches. As such, some parts have to be made using hardened steel (or steel inserts) rather than the softer materials typically used in R&D tooling, like aluminum.

Additionally, material selection will also play a role in moldmaking. Some plastic materials do not interface well with certain mold materials. For instance, a part made with glass-filled nylon, even in prototype, will need to be molded in a higher quality mold than a part made in standard polypropylene.

When reviewing geometry and complexity, Natech&#;s engineers also examine overall functionality to guide mold selections. Are there any living hinges, snap fits, breakaways, or downstream integrations that need to be considered before correctly selecting a mold?

Quantity of Parts to be Produced

Finally, you&#;ll want a general baseline for the number of parts you want to produce from this mold. Is this a &#;test&#; mold that will only run a few hundred parts? Or, are you hoping this will be the mold that takes you into millions or tens of millions of parts?

You may have a firm design that is unlikely to change, but still only need an R&D or pre-production mold because you only expect to need a few thousand parts. Conversely, you may have a design that may change but is highly complex with fine features. A good option is a mold that has hardened steel inserts, which costs more, but allows the flexibility of change until you firm up your final design.

Understanding SPI Mold Classifications

First, you want to understand that not all molds are created equally.  Different mold materials and mold construction methods serve different purposes.  Fortunately, the Plastics Industry Association, formerly SPI, developed a mold classification system that introduced a standard to the industry. This system helps mold buyers to make apples-to-apples comparisons and understand the tradeoffs of each option. 

For example, an Aluminum mold (class 104) might be faster and cheaper to build, but it will not last as long. These molds are recommended for when you are still proving out a concept or only need 10,000 or fewer parts.

A hardened steel mold (class 101 or 102) might last for 1,000,000+ cycles, but the initial cost will be much higher. Steel molds are recommended when you have a finalized design and are ready to manufacture 500,000+ parts.

The SPI categorized the molds into five separate classes ranging from a Class 105 prototype mold up to a more robust Class 101 mold. 

The standard details:

• Specific hardness of various components of the mold
• Construction approaches
• Type of material typically processed
• Number of cycles to be expected
• General minimum cost 

Mold classifications outline the properties for all 5 categories and cover molds that operate for less than 500 cycles (Class 105 mold) and molds that run up to over a million cycles (Class 101 mold).

Mold Class 105:

For companies looking to only make 100-500 parts, a class 105 mold will likely be the best fit. While the initial investment is low, they cannot be expected to produce beyond a few hundred parts. This is recommended for very early stage prototyping only.

Mold Class 104:

In general, medical and biotech startups with a design will start with a class 104 aluminum mold, as long as the geometry, plastic material, and post-manufacturing processes are aligned. After their concept is proved out, they move to a single cavity (making one part at a time) steel mold, and then onto a multi-cavity (making many parts at a time) steel mold.

This method allows companies to responsibly prove out their concepts, test the market, plan for investments and ramp up production without overextending their cash or their molds.

Mold Class 102 & 103:

Class 103 and 102 molds are good options for companies with a firm part design that they want to be produced in medium-to-high volume. Natech&#;s engineers evaluate the materials being used, the part geometry and complexity, and the future planning for the project to help clients select the right mold.

Mold Class 101:

Class 101 molds are often reserved for complex, medical parts that will be produced in the tens of millions. These molds last for a long time but come with the associated price tag. Clients in need of class 101 molds will likely not have any design changes and have a clear, confident, and consistent forecast of high-volume orders.

Prepare for Your Mold RFP

When it is time to request proposals from manufacturing partners, it is important to be prepared to answer these five questions. There is no right or wrong answer to any of these questions. Instead, being honest about goals and expectations early allows your manufacturing partner to help you select the best path forward.

Question: What is your budget?

Why we ask: The manufacturer wants to know a few things about you and your team. This helps them to understand if you have done your research and if you have realistic expectations. Additionally, they may be trying to understand if your company is a good fit for them.

Some companies specialize in working with and building specific types of molds that have a specific price tag. Understanding what you are expecting to spend allows them to begin to guide the selection process. Understand that at a minimum, you&#;ll need to invest at least $5,000 &#; $10,000 for an initial prototype mold.

Being transparent with your budget also opens the door to creative problem solving. Overstating your budget may lead to you getting a mold that you don&#;t need or aren&#;t ready for yet. Understating your budget can leave you without specialty mold features that could save you money and improve your quality over the long haul.

Question: What&#;s your target piece price?

Why we ask: Similar to your budget, understanding your target piece price allows them to begin the mental planning for the future of your project. If you currently have a large budget and a low target piece price, depending on the state of your design, getting a steel, multi-cavity mold built may be the best solution.

However, if you&#;re hoping for a low target piece price in the future, but have a constrained budget, starting with an aluminum mold to get parts in hand could be the best path as your build up capital to invest in a high-production mold.

Question: How critical is your timeline?

Why we ask: Of course, most people want their parts in hand yesterday. However, speed isn&#;t always your friend. Natech&#;s engineers ask this question to design a path forward for your mold and set expectations.

For instance, if you need parts in hand ASAP, but are ordering in high volumes, getting an R&D mold and a steel mold built consecutively may be advantageous. It allows you to produce a small number of parts while waiting for your production mold to be built. If you have a more flexible timeline, you can save money by building a mold that meets your demands at your development stage.

Question: What are the tolerances on the part?

Why we ask: As mentioned earlier, some molds are not conducive for specific tolerances. This means that even in R&D, getting an aluminum mold may not be feasible. If you are still in proof of concept but have a part design that is complex and required to hold tight tolerances, you may need to jump into steel or examine using steel inserts.

On the flip side, you may have a less complex part that doesn&#;t require maintaining fine features. This could allow you to purchase a Class 103 or 104 mold rather than spending money on a higher class mold that doesn&#;t result in better value or quality for you.

Question: Is the design open to changes for Design for Manufacturing (DFM)?

Why we ask: When it comes to mold building and part design, most designs require some amount of DFM before building a mold. If you are asked this question, it is likely, the part has been reviewed and needs some tweaking before a mold can be successfully built. Customers who are open to changes for DFM signal to their manufacture that they &#;get it,&#; and are willing to invest a little for a long-term payoff.

However, some mold building shops are willing to build a mold without DFM. This introduces risk to your part, as it may not be ready for injection molding or may result in quality issues. These issues lead to increased costs in molding and mold repairs down the line.

Learn more about Design for Manufacturing.

Red Flags in Your Mold Selection Process

As with any investment, it is important to not only prepare and research in advance but to understand the red flags you need to watch out for. While every experience is different, below are the top red flags we&#;ve had customers encounter in the past, which ended up costing them time and money later.

Red Flag #1: Few or No Project Questions

What it means: If you request a proposal that includes a mold, you can expect to get at least 5-10 different questions coming in from the supplier. However, if you don&#;t seem to get any, then beware. This can mean that the company isn&#;t invested in you or your project, they aren&#;t interested in your input, or they don&#;t care to learn and collaborate further.

For some, the number of questions they receive from Natech&#;s engineers upfront can seem daunting. However, it also means that the proposal you receive back is customized to your needs and that we&#;re willing to work and collaborate on a deeper level.

Red Flag #2: Misleading Lead Times

What it means: Lead times should include both mold design and mold build. However, some will quote just the mold design or the mold build &#; but not both. Quoting a lead time for just one or the other is disingenuous, but we&#;ve had clients come and say they fell victim to this in the past. Often, this is done to make the customer think they will get their parts faster. Instead, it skews your own timeline and expectations.

When you are working through your proposal, make sure the quoted lead time includes design updates and the mold build itself.

Red Flag #3: Taking a Long Time to Receive a Quote

What it means: While every quote is different, companies should get you a quote in a timely fashion. Even more so, they should tell you when you can anticipate having a proposal in hand. If a company takes a long time, misses commitments or doesn&#;t share their timeline with you in the proposal phase, it is unlikely that&#;ll change through the life of your project. This should signal a lack of internal accountability and poor communication. Both of which hurt your project and your bottom line.

If the information isn&#;t shared upfront, ask when you can anticipate having a quote delivered &#; and keep an eye on if they can keep that initial commitment.

Red Flag #4: Long, Generic Proposal

What it means: When you are getting a quote for a mold, you want the most important information upfront and tailored to your program. Too often, companies try to skirt the process and deliver a long, generic proposal in the hopes that you either a.) won&#;t read the whole proposal, and they&#;ll get the upper hand on you, or b.) won&#;t notice that the proposal isn&#;t specific to your needs.

Either way, these types of proposals end up taking an unnecessary amount of time to work through or leave you agreeing to items that don&#;t make sense for your project.

Summary

Investing in the right mold for your project shouldn&#;t be a mysterious process. Instead, by working with a trusted manufacturing partner, they can walk you through each step. This means that more of your time and money can be invested in the tool that&#;s right for your job right now.

Natech has worked with hundreds of entrepreneurs, start-ups, and corporations to design their parts, build their molds, and manufacture their parts. We believe in developing a collaborative relationship with clients to help them launch and scale their projects successfully.

Understanding the Concept of Injection Molding Prototype

Conceptually, an injection molding prototype serves as a critical step in the product development cycle. It&#;s a powerful tool for creating a physical product from a CAD model that mirrors the design and functionality of the final product. Building an injection molding prototype leverages the plastic mold prototype making process, incorporating a wide range of materials which aid in determining the viability of the design and its potential for mass production.

The journey of how to make a plastic mold prototype starts with feeding raw material, usually thermoplastic polymers, into a machine. This material is heated until malleable, then injected into a mold cavity designed according to the CAD model. The material cools and solidifies, adopting the shape of the mold to give a plastic prototype reflecting the shape and dimensions of the intended final product. This plastic prototype manufacturing process enables fabricators to optimally design and make adjustments before proceeding to full-scale production, thereby saving time, reducing tooling costs, and enhancing the product&#;s quality.

The Importance of Prototyping in the Injection Molding Process

In the context of product development, prototyping plays an integral role. Specifically, creating a prototype injection molding machine model is a cost-efficient way of identifying and rectifying any design flaws at early stages. Imagine you&#;re working on a new product, perhaps a piece of custom consumer electronics or an innovative kitchen gadget for a wide range of materials. Before diving directly into mass production, you&#;d want to ensure the idea is practical and cost-effective.

Making a plastic prototype is crucial for not only evaluating the idea, but also for demonstrating this concept to potential investors or stakeholders. An injection molding prototype helps to physically visualize the concept in 3D, communicate the idea more efficiently, and receive constructive feedback early in the game. Prototyping also allows ample room for design flexibility and iteration in injection molding prototyping, streamlining further design processes.

What is the process of making an injection molding prototype?

The process of making an injection molding prototype is a fascinating journey from a concept to a tangible product. It begins with a CAD model, which is a computer-aided design of the product. This model is then used to create a mold design, which is essentially a negative of the product. The mold is typically made from aluminum or steel, and it&#;s where the magic happens.

Once the mold is ready, it&#;s placed in the injection molding machine. Raw material, usually plastic, is fed into the machine, where it&#;s heated until it becomes liquid. This molten plastic is then injected into the mold under high pressure. As the plastic cools, it solidifies and takes the shape of the mold. The resulting cast is a plastic prototype, a physical representation of the product that can be tested for functionality and design.

This process is not only a cost-effective way to create prototypes but also a powerful tool for testing and refining designs. It allows for a short period of time to make adjustments and improvements before moving on to mass production. And with the use of injection, even complex shapes with undercuts can be achieved, offering a competitive advantage in various industries.

The Role of 3D Printing in Creating Injection Molding Prototypes

3D printing has revolutionized the world of prototyping, offering a rapid and cost-efficient way to create physical models from digital designs. In the context of injection molding, 3D printing can be used to create prototype molds, thereby speeding up the prototyping process and reducing costs.

Link to Shbury

The process involves using a 3D printer to create a mold from a CAD model. This mold can then be used in the injection molding process to create a plastic prototype. The advantage of this method is that it allows for quick iteration and testing of designs without the need for expensive tooling.

However, it&#;s important to note that while 3D printing is a powerful tool for prototyping, it may not always be the best choice for every project. Factors such as the complexity of the design, the required material properties, and the intended production volume should all be considered when choosing between 3D printing and traditional injection molding for prototyping.

Comparing Rapid Prototyping Methods: 3D Printing vs. Injection Molding

When it comes to rapid prototyping, both 3D printing and injection molding have their unique advantages. 3D printing, often associated with plastic prototype manufacturing, allows for quick turnarounds and is especially useful for low-volume production. It&#;s a go-to for many who wonder how to get a plastic prototype made in a short period of time. The process is direct: from a CAD model to a physical product without the need for molds.

On the other hand, injection molding, while initially more time-consuming due to the mold-making process, becomes highly efficient for larger production runs. The prototype injection molding machine can produce multiple copies of a part in a relatively short period of time once the mold is created.

To better understand the differences, let&#;s compare these two methods in a table:

Both methods have their place in the prototyping process. 3D printing is excellent for initial prototypes and design iteration, while injection molding is often the preferred choice for later-stage prototyping and final product manufacturing.

How Injection Molding Prototype Streamlines Product Development

Product development is a complex process, often involving numerous iterations and extensive testing. An injection molding prototype can significantly streamline this process, providing a cost-effective way to test and refine designs before moving on to mass production.

The prototype injection molding process allows for the creation of a physical product that can be tested for functionality, durability, and user experience. This hands-on testing can reveal design flaws or areas for improvement that may not be apparent in a digital model. By identifying and addressing these issues early in the development process, companies can avoid costly redesigns and production delays.

Moreover, injection molding prototypes can be used to demonstrate the product to potential investors, stakeholders, or customers. This can be a powerful tool for gaining feedback, securing funding, or generating pre-launch buzz. By making a plastic prototype, companies can also gauge market interest and gather valuable user feedback before committing to full-scale production.

The Economic Benefits of Injection Molding Prototype

From an economic perspective, investing in an injection molding prototype can yield significant benefits. While there are upfront costs associated with creating the mold, these can be offset by the savings realized through early identification and resolution of design issues.

In addition, the cost per unit of an injection molded part decreases with volume, making it a cost-efficient way for mass production. This is particularly beneficial for companies planning to produce a high volume of products. The prototype mold making process also allows for the use of a wide range of materials, including less expensive plastics, further contributing to cost savings.

Furthermore, having a physical prototype can help secure funding from investors or pre-orders from customers, providing an early source of revenue. It also reduces time-to-market, allowing companies to start selling their products sooner.

Achieving High Precision with Injection Molding Prototyping

When it comes to high precision and consistency, the injection molding prototype process stands out. The use of CAD models and CNC machining to create aluminum or steel molds means that each and every part produced is virtually identical. This consistency is crucial in industries like healthcare, aerospace, and automotive where a tiny variation can have big consequences.

On top of that, injection molding allows for complex geometries and designs that other methods might struggle to replicate accurately. The raw material is injected into the mold under high pressure, which helps to fill any small or intricate features in the mold, resulting in parts that closely match the original design.

In context, that&#;s how to make a plastic mold prototype with a high degree of precision, offering the advantage of producing more complex and accurate prototypes in comparison to other methods. This precision, coupled with relatively high output rates once molds are created, makes injection molding prototyping a viable choice for projects with detailed requirements and high volume needs.

Material Versatility in the Injection Molding Prototype Process

Injection molding offers unparalleled versatility in terms of the materials that can be used. Unlike 3D printing, which can typically only utilize a specific type of plastic or resin, injection molding can accommodate a wide array of materials. The most commonly used is a variety of thermoplastic polymers, which offer a range of properties to meet the requirements of different applications.

Materials commonly used in injection molding include ABS, polycarbonate, nylon, and various types of polyethylene, each bringing its own set of properties to the table. ABS is known for its toughness and impact resistance, whereas polycarbonate is used for its excellent clarity and heat resistance.

The resulting cast from the injection molding process can then be further treated or modified as necessary, for example through painting, metallization, or the application of other surface treatments. This flexibility in material choice and post-processing allows for a great deal of customization and optimization, enabling the production of prototypes that closely mimic the final product&#;s functionality and aesthetics.

Design Flexibility and Iteration in Injection Molding Prototyping

One of the key advantages of using an injection molding prototype in product development is the flexibility it offers in terms of design and iteration. While the initial creation of the mold requires a certain investment of time and resources, once it&#;s made, it can be used to produce multiple copies of the part quickly and efficiently.

This allows for rapid iteration and testing of designs. If a design flaw is identified in the prototype, the CAD model can be adjusted and a new mold created. This process can be repeated as many times as necessary until the design is perfected. This is particularly beneficial in the early stages of product development, where designs often undergo significant changes.

Moreover, injection molding is capable of producing complex and intricate designs that might be difficult or impossible to achieve with other prototyping methods. This includes features like undercuts, threads, and inserts, which can be incorporated directly into the mold design.

How Prototype Injection Molding Reduces Time-to-Market

In today&#;s fast-paced market, speed is of the essence. Companies are under constant pressure to develop and launch new products as quickly as possible. Prototype injection molding can play a crucial role in reducing time-to-market.

By allowing for early detection and resolution of design issues, injection molding prototypes can help avoid costly delays later in the production process. They also enable companies to test and validate their designs quickly, accelerating the development cycle.

Furthermore, once the mold is created, parts can be produced at a high rate, making it possible to move from prototyping to mass production in a relatively short period of time. This can give companies a competitive advantage, allowing them to get their products to market faster than their competitors.

Production Equivalency: The Key Advantage of Injection Molding Prototypes

Perhaps one of the most compelling advantages of injection molding prototypes is the seamless transition they provide from the prototype stage to full-scale production. The prototype plastic injection molding process uses the same materials, machinery, and tooling as the final production stage, which is an immense advantage when you&#;re aiming for production equivalency.

The prototypes produced through injection molding aren&#;t simply rough drafts of the final product&#;they mirror exactly how the final product will look and perform. This level of equivalency goes beyond physical properties; prototypes can also incorporate colors, textures, and finishes that the final product will feature.

It&#;s hard to overstate the importance of this. When stakeholders can see and feel a prototype that matches the finished product quality, it greatly instills confidence in the product&#;s success. This advantage also extends to the product testing phase, as the findings from prototype tests can be directly applied to full-scale production.

Innovation and Creativity in the Injection Molding Prototype Process

Prototyping, including injection molding prototype creation, is an exciting phase in the product development process. It&#;s where the rubber meets the road &#; concepts turn into physical objects, ideas turn into reality. This space is ripe for creativity and innovation.

The feasibility of complex designs, the range of materials accessible, and the process&#; inherent nature to refine an idea make prototype injection molding a powerful tool for innovation. Designers can experiment with new shapes, incorporate novel features, and trial unconventional materials. Mistakes here cost less and teach more compared to later production stages.

The system is designed to iterate, innovate, and improve. By making a plastic prototype, we learn, adapt, and get better, not just in the context of a single product, but evolving the broader understanding of manufacturing capabilities and constraints.

Sustainability Considerations in Injection Molding Prototyping

Sustainability is an increasingly important factor in manufacturing practices, and injection molding prototyping isn&#;t exempt from these considerations. When it comes to environmental impact, different stages of the prototype injection molding process have various factors to consider.

Here&#;s a table outlining some aspects:

The industry is continuously exploring new methods, materials, and technologies to reduce the environmental impact, including researching biodegradable plastics and developing more efficient machines.

The Future of Injection Molding Prototypes: Trends and Predictions

As we forge ahead into the future, the process of making an injection molding prototype will continue to evolve. New materials with enhanced properties, such as biodegradable plastics and composites, are expected to emerge. Technologies like AI and machine learning are anticipated to make the process more efficient and accurate.

In terms of trends, we can expect to see even greater synergy between prototyping methods as the lines between processes like injection molding and 3D printing become ever more blurred. Despite what the future holds, one thing is clear: injection molding prototypes will continue to play an essential role in product design and development.

Case Studies: Successful Products Developed Using Injection Molding Prototypes

There are numerous examples of successful products that started their journey as injection molding prototypes. Let&#;s look at a couple of case studies:

1. Consumer Electronics: A leading tech company wanted to develop a new, ergonomic game controller. They used injection molding prototyping to create a series of prototypes, each with slight variations in design. This allowed them to test each version thoroughly, gather user feedback, and refine the design based on this feedback. The final product was a hit, praised for its comfortable design and user-friendly features.
2. Automotive Industry: A car manufacturer was designing a new model and wanted to test several different dashboard designs. They used injection molding to create full-scale prototypes of each design, which were then installed in test vehicles. This allowed them to evaluate each design in a real-world context and make informed decisions about the final design.

These case studies highlight the versatility and effectiveness of injection molding prototypes in product development across a range of industries.

Conclusion

From understanding the concept to exploring its economic benefits, it&#;s clear that injection molding prototyping is a powerful tool in product development. It offers high precision, material versatility, design flexibility, and production equivalency, all while reducing time-to-market. With sustainability considerations and future trends in mind, the injection molding prototype process is set to continue playing a pivotal role in bringing innovative, successful products to market.

Opt for FOWmould

When it comes to reliable and high-quality injection molding prototyping, FOWmould stands out. With a proven track record, the extensive network of partners, and commitment to innovation, FOWmould is the go-to choice for businesses seeking to streamline their product development process and bring successful products to market.